Exclude 3DES tests in test scripts
diff --git a/tests/compat.sh b/tests/compat.sh
index a2b2d5b..eefebd0 100755
--- a/tests/compat.sh
+++ b/tests/compat.sh
@@ -53,7 +53,11 @@
VERIFIES="NO YES"
TYPES="ECDSA RSA PSK"
FILTER=""
-EXCLUDE='NULL\|DES-CBC-\|RC4\|ARCFOUR' # avoid plain DES but keep 3DES-EDE-CBC (mbedTLS), DES-CBC3 (OpenSSL)
+# exclude:
+# - NULL: excluded from our default config
+# - RC4, single-DES: requires legacy OpenSSL/GnuTLS versions
+# avoid plain DES but keep 3DES-EDE-CBC (mbedTLS), DES-CBC3 (OpenSSL)
+EXCLUDE='NULL\|DES-CBC-\|RC4\|3DES\|ARCFOUR'
VERBOSE=""
MEMCHECK=0
PEERS="OpenSSL$PEER_GNUTLS mbedTLS"